Resistance training -- which is often overlooked in stroke rehab -- may help improve thinking and memory in stroke survivors, researchers found.

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This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

In this study, a 6-month exercise program of combined aerobic and resistance training resulted in significant improvements in cognitive function in patients with motor impairments at least 10 weeks post stroke.

Resistance training -- which is often overlooked in stroke rehab -- may help improve thinking and memory in stroke survivors, researchers found.

Overall, cognitive tests revealed that both resistance training and aerobic exercise contributed to improvements in cognition at 6 months, according to Susan Marzolini, BPHE, MSc, of the Toronto Rehabilitation Institute, and colleagues.

But a linear regression model revealed a significant positive association between change in cognitive function and change in muscle mass (P=0.005), independent of sex, time from stroke, and change in fat mass and depression score, Marzolini reported at the Canadian Stroke Congress in Calgary.

"Unfortunately, resistance training is not a standard component of stroke rehab," Marzolini told MedPage Today. "To measure the muscle mass, we used dual-energy x-ray absorptiometry, which is a very precise method. We found that the greater the improvement in muscle mass, the greater the improvement in cognition."

The muscles most affected by stroke in this study involved those for walking -- in particular, the hip flexors, which help raise the knees up, and the pretibial muscles in front of the shins, which help lift the toes up, Marzolini said.

"Whereas many rehab centers would have stroke patients only move their legs, we are adding weight. The intensity of the amount of weight is the key to their improvement," she said.

To add weight training to the patients' routines, Marzolini determines the heaviest weight a patient can lift, cuts that by half, and then proceeds with 10 repetitions. The reps are increased incrementally. When the patient is ready for more weight, he or she drops back down to 10 reps.

Patients also use resistance bands to strengthen their weak muscles.

Resistance training has added benefits as well. Researchers noted an overall 30% improvement in strength on both sides of the body.

Marzolini and colleagues also found a significant association between positive changes in attention and concentration and aerobic exercise, as measured by maximal oxygen consumption. This too was independent of sex, time from stroke, and change in fat mass and depression score (P<0.001).

The study included 41 patients who suffered mild or moderate stroke. The mean age was 63, and 70% of patients used some type of walking aid. The time from stroke to the start of rehab varied and ranged from several months to 5 years.

Using the Montreal Cognitive Assessment test, researchers found that the combined training program resulted in a significant overall improvement in cognition (22 to 24, P<0.001), and specifically in attention and concentration (4.7 to 5.0, P=0.03) at 6 months post rehab.

Patients also significantly improved their visuospatial and executive function (3.4 to 3.9, P=0.002), while the proportion of patients identified as having mild cognitive impairment significantly dropped from 65.9% to 36.6% (P<0.001).

Marzolini said that her team is getting ready for the next part of this research, which is a study randomizing stroke patients to aerobic and resistance training or just resistance training.

"I suspect aerobic and resistance training are working synergistically," she said.

However, each form of exercise releases unique growth factors, which also will be measured, as will markers of inflammation.

"The bottom line is that exercise is very important for everyone, but especially for stroke patients, and rehab programs should include both aerobic and strength training," she concluded.